package com.sicheng.lc.周赛.分类.dp.字符串;

/**
 * @author zsc
 * @version 1.0
 * @date 2022/7/19 20:38
 */
public class 正则表达式匹配 {
    //https://leetcode.cn/problems/regular-expression-matching/
    public boolean isMatch(String s, String p) {

        int m = s.length();
        int n = p.length();
        boolean[][] dp = new boolean[m + 1][n + 1];
        dp[0][0] = true;
        int i = 0;
        for (int j = 1; j <= n; j++) {
            if (j >= 2)
                dp[i][j] = (p.charAt(j - 1) == '*' && dp[i][j - 2]);
            else
                dp[i][j] = p.charAt(j - 1) == '*';
        }

        for (i = 1; i <= m; i++) {
            char c1 = s.charAt(i - 1);
            for (int j = 1; j <= n; j++) {
                char c2 = p.charAt(j - 1);
                if (c2 == '*') {
                    if (j >= 2)
                        dp[i][j] |= dp[i][j - 2] | (dp[i - 1][j] & (c1 == p.charAt(j - 2) || p.charAt(j - 2) == '.'));
                } else if (c2 == '.' || c2 == c1) {
                    dp[i][j] |= dp[i - 1][j - 1];
                }
            }
        }

        return dp[m][n];
    }

    public static void main(String[] args) {
        正则表达式匹配 s = new 正则表达式匹配();
        System.out.println(s.isMatch("a", ".*..a*"));
    }
}
